An antioxidant and flame-retardant PET masterbatch and its preparation method

Abstract

This invention relates to the field of polymer materials technology, specifically to an antioxidant and flame-retardant PET masterbatch and its preparation method. The invention involves adding PET, antioxidant-modified titanium dioxide, flame-retardant modified titanium dioxide, antioxidant and flame-retardant agents, dispersants, and lubricants, stirring and dispersing them evenly, followed by melt blending, extrusion granulation, and finally obtaining the finished product. The finished product prepared by this invention possesses excellent antioxidant and flame-retardant properties, thus having broad application prospects in the field of polymer materials technology.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an antioxidant and flame-retardant PET masterbatch and its preparation method. Background Technology

[0002] Against the backdrop of the large-scale development of the polyester industry, PET masterbatch coloring offers advantages such as precise measurement and ease of operation, significantly improving the appearance stability and batch consistency of PET products. It meets the requirements of high-end products for color purity and durability, aligning with the needs of modern production. However, PET material itself has limited stability. During long-term use, it is susceptible to oxidative degradation due to oxygen and light, leading to yellowing, brittleness, and decreased mechanical properties, failing to meet long-term usage requirements. Furthermore, PET is a flammable material, easily ignited and rapidly burning. Masterbatch without flame retardant properties, when applied to various products, can easily cause fire hazards, especially in safety-critical fields such as electronics, packaging, and textiles, where flame retardancy is essential.

[0003] To overcome the shortcomings of the prior art, the present invention provides an antioxidant and flame-retardant PET masterbatch and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an antioxidant and flame-retardant PET masterbatch and its preparation method, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing antioxidant and flame-retardant PET masterbatch includes the following steps: mixing PET, modified pigment, antioxidant and flame-retardant, dispersant and lubricant, stirring and dispersing evenly, then melt-blending and extruding granulation to obtain the finished product; The modified pigments include antioxidant modified titanium dioxide and flame-retardant modified titanium dioxide. The antioxidant modified titanium dioxide is obtained by loading the biomass antioxidant curcumin onto the surface of titanium dioxide pigment. The flame-retardant modified titanium dioxide is obtained by grafting flame-retardant bicyclic products onto the surface of titanium dioxide pigment. The antioxidant flame retardant is obtained by grafting phosphorus heterocyclic flame retardant materials onto the surface of lignin, an antioxidant material.

[0006] In a more optimized manner, the content of each component in the finished product is as follows (by mass fraction): 55-65% PET, 10-15% antioxidant modified titanium dioxide, 5-10% flame retardant modified titanium dioxide, 20-25% antioxidant flame retardant, 2-3% dispersant, and the balance being lubricant.

[0007] More preferably, the dispersant is polyethylene wax; the lubricant is calcium stearate; and the melt blending temperature is 250-280℃.

[0008] A more optimized preparation process for antioxidant modified titanium dioxide is as follows: Step S1: Mix γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water, and stir at 60-65℃ for 2.5-3.5 h to obtain a hydrolysate; mix titanium dioxide, anhydrous ethanol, and deionized water, and stir and disperse for 20-30 min to obtain a dispersion; mix the hydrolysate and the dispersion, and stir and react at 25-30℃ for 2.5-3.5 h. After the reaction is completed, distill under reduced pressure, wash, and dry to obtain modified titanium dioxide. Step S2: Mix curcumin and ethanol aqueous solution, stir and dissolve at 25-30℃, then add modified titanium dioxide, continue stirring and reacting for 30-40 minutes. After stirring, centrifuge, wash and freeze dry to obtain antioxidant modified titanium dioxide.

[0009] In a more optimized manner, in step S1, when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water is (0.8-1.0):4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water is (0.2-0.3):8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide is (1.1-1.2):1; and in step S2, the mass ratio of curcumin to modified titanium dioxide is (1.3-1.5):2.

[0010] A more optimized preparation process for flame-retardant modified titanium dioxide is as follows: Step 1: Mix γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water, and stir at 60-65℃ for 2.5-3.5 h to obtain a hydrolysate; mix titanium dioxide, anhydrous ethanol, and deionized water, and stir and disperse for 20-30 min to obtain a dispersion; mix the hydrolysate and the dispersion, and stir and react at 25-30℃ for 2.5-3.5 h. After the reaction is completed, distill under reduced pressure, wash, and dry to obtain modified titanium dioxide. Step 2: Under nitrogen atmosphere, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene are mixed and reacted at 65-70℃ for 2.0-3.0h, then the temperature is raised to 95-100℃ for 8-9h. After the reaction is completed, the mixture is cooled, filtered, washed, and dried to obtain the bispirocyclic product. Under nitrogen atmosphere, the bispirocyclic product, modified titanium dioxide, and acetonitrile are mixed, and then triethylamine is added dropwise. After the addition is completed, the temperature is raised to 80-85℃ for 20-25h. After the reaction is completed, the mixture is rotary evaporated and dried to obtain the flame-retardant modified titanium dioxide.

[0011] In a more optimized manner, in step 1, when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water is (0.8-1.0):4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water is (0.2-0.3):8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane and titanium dioxide is (1.1-1.2):1; in step 2, when preparing the bispirocyclic product, the mass ratio of pentaerythritol, phosphorus oxychloride, and 4-dimethylaminopyridine is 27:(80-85):0.1; when preparing the flame-retardant modified titanium dioxide, the mass ratio of the bispirocyclic product, modified titanium dioxide, and triethylamine is 3:(10-12):2.

[0012] A more optimized preparation process for antioxidant flame retardants is as follows: Step (1): Add sodium lignosulfonate to sodium hydroxide solution, stir to dissolve, then add epoxybromopropane, stir evenly, and heat to 55-60℃ for 25-30h. After the reaction is completed, precipitate, filter and dry to obtain epoxidized lignin. Step (2): Add epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to N,N-dimethylformamide, stir evenly, and then heat to 120-130℃ for 5-6 hours. After the reaction is completed, the antioxidant flame retardant is obtained by rotary evaporation, washing and drying.

[0013] In a more optimized manner, in step (1), the mass ratio of sodium lignosulfonate to epoxide is 1:(2.0-2.5); the concentration of sodium hydroxide solution is 7-10wt%; and in step (2), the mass ratio of epoxide lignin to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(0.7-0.9).

[0014] The beneficial effects of this invention are: The key feature of this invention is the mixing of γ-aminopropyltriethoxysilane, anhydrous ethanol, deionized water, and titanium dioxide. The silanol generated from the hydrolysis of the silane molecules undergoes a dehydration condensation reaction with the hydroxyl groups (Ti-OH) on the surface of the titanium dioxide, forming strong Si-O-Ti covalent bonds to obtain modified titanium dioxide. During this process, an organosilicon layer with -NH2 functional groups is connected to the surface of the titanium dioxide through Ti-O-Si bonds. This treatment can, on the one hand, reduce the agglomeration of titanium dioxide and improve its uniformity in the system; on the other hand, it can introduce highly reactive terminal amino groups. Furthermore, curcumin, an aqueous ethanol solution, and modified titanium dioxide are mixed. The amino groups on the surface of the modified titanium dioxide provide numerous binding sites, allowing curcumin to be loaded onto the surface of the modified titanium dioxide through hydrogen bonds and van der Waals forces, resulting in antioxidant modified titanium dioxide. Curcumin is a natural and highly effective antioxidant; the curcumin molecule contains two phenolic hydroxyl groups at both ends, which can effectively scavenge free radicals. Therefore, by combining the highly effective antioxidant curcumin with titanium dioxide through amination modification, the synergistic effect of antioxidant stabilization and high loading was achieved, resulting in an antioxidant-modified titanium dioxide with excellent and long-lasting antioxidant properties.

[0015] The key feature of this invention is the mixing of γ-aminopropyltriethoxysilane, anhydrous ethanol, deionized water, and titanium dioxide to obtain modified titanium dioxide. The modified titanium dioxide surface is grafted with organosilane chains terminally containing amino groups, providing initial nitrogen for subsequent nitrogen-phosphorus synergistic flame retardancy. Furthermore, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene are mixed to undergo a nucleophilic substitution reaction, yielding a bispirocyclic product. The bispirocyclic product, modified titanium dioxide, and triethylamine are then mixed, and the amino groups and phosphoryl chloride undergo a nucleophilic substitution reaction to obtain flame-retardant modified titanium dioxide. This flame-retardant modified titanium dioxide surface exhibits a high-density phosphorus-nitrogen flame-retardant structure covalently bonded via phosphoramide bonds. By fixing the phosphorus-nitrogen flame-retardant system to the titanium dioxide surface through covalent bonds, excellent flame retardancy can be achieved.

[0016] The key feature of this invention is that sodium lignosulfonate, sodium hydroxide solution, and epoxybromopropane are mixed. Under alkaline conditions, the phenolic hydroxyl groups in the sodium lignosulfonate structure are activated by sodium hydroxide, generating a phenoxy anion with strong nucleophilicity. The phenoxy anion undergoes a nucleophilic substitution reaction with the brominated methyl site of epoxybromopropane to obtain epoxidized lignin. Furthermore, epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed, and the pH bond and epoxy group undergo a ring-opening reaction to obtain an antioxidant flame retardant. Specifically, by bonding DOPO groups to the lignin skeleton, DOPO provides highly efficient phosphorus-based flame retardant activity and a rigid char-forming phenanthrene ring; lignin provides a large amount of intrinsic char-forming carbon source and skeleton. After being chemically bonded, the two synergistically catalyze and cross-link during combustion, forming an extremely strong, dense, and continuous expanded char layer, maximizing the synergistic flame retardant effect. Moreover, the sodium lignosulfonate molecule contains abundant phenolic hydroxyl groups, exhibiting excellent antioxidant properties. Therefore, the prepared antioxidant flame retardant has excellent flame retardancy and antioxidant properties.

[0017] The key feature of this invention is that by adding PET, antioxidant-modified titanium dioxide, flame-retardant-modified titanium dioxide, antioxidant flame retardant, dispersant, and lubricant, and after uniform dispersion by stirring, the mixture is melt-blended, extruded, and granulated to obtain the finished product. Traditional masterbatches involve a simple physical dry mixing of PET, pigments (titanium dioxide), antioxidants, and flame retardants, followed by melt extrusion. This method relies solely on intermolecular forces to bind the components, resulting in poor compatibility and a high risk of phase separation and migration / precipitation of functional additives during subsequent processing and use. This invention, before blending the functionalized materials (antioxidant / flame retardant materials) with the PET matrix, first uses surface modification technology to anchor them to the surface of the titanium dioxide, effectively solving the dispersion and stability problems during the functionalization of polymer materials, thereby significantly improving the overall performance of the material. Therefore, the finished product prepared by this invention possesses excellent antioxidant and flame-retardant properties, and thus has broad application prospects in the field of polymer materials technology. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Raw material source: Titanium dioxide, particle size 200nm; sodium lignosulfonate, hydroxyl content 3.0-3.5mmol / g; PET, provided by Shanghai Shengyu Plastics Co., Ltd., grade FC02BK507; polyethylene wax, provided by Wuhan Lingfan Technology Co., Ltd., CAS number 9002-88-4.

[0020] Example 1: Step S1: γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water were mixed and stirred at 65°C for 3.5 h to obtain a hydrolysate; titanium dioxide, anhydrous ethanol, and deionized water were mixed and stirred for 30 min to obtain a dispersion; the hydrolysate and dispersion were mixed and stirred at 30°C for 3.5 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed, and dried to obtain modified titanium dioxide; when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water was 0.9:4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water was 0.25:8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide was 1.15:1. Step S2: Mix curcumin and ethanol aqueous solution, stir and dissolve at 30℃, then add modified titanium dioxide, continue stirring and react for 40 min. After stirring, centrifuge, wash and freeze dry to obtain antioxidant modified titanium dioxide; the mass ratio of curcumin to modified titanium dioxide is 1.4:2. Step S3: Under nitrogen atmosphere, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene were mixed and reacted at 70℃ for 3.0 h, then the temperature was raised to 100℃ and reacted for 9 h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain a bispirocyclic product. Under nitrogen atmosphere, the bispirocyclic product, modified titanium dioxide, and acetonitrile were mixed, and triethylamine was added dropwise. After the addition was completed, the temperature was raised to 85℃ and reacted for 25 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain flame-retardant modified titanium dioxide. When preparing the bispirocyclic product, the mass ratio of pentaerythritol, phosphorus oxychloride, and 4-dimethylaminopyridine was 27:82:0.1. When preparing the flame-retardant modified titanium dioxide, the mass ratio of the bispirocyclic product, modified titanium dioxide, and triethylamine was 3:11:2. Step S4: Add sodium lignosulfonate to sodium hydroxide solution, stir to dissolve, then add epoxide bromide, stir evenly, and heat to 60℃ for 30 hours. After the reaction is complete, precipitate, filter, and dry to obtain epoxide lignin; the mass ratio of sodium lignosulfonate to epoxide bromide is 1:2.3; the concentration of sodium hydroxide solution is 8 wt%. Step S5: Epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to N,N-dimethylformamide, stirred evenly, and then heated to 130℃ for 6 hours. After the reaction was completed, the mixture was rotary evaporated, washed, and dried to obtain an antioxidant flame retardant. The mass ratio of epoxidized lignin to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was 1:0.8. Step S6: By mass fraction, mix 62% PET, 10% antioxidant modified titanium dioxide, 5% flame retardant modified titanium dioxide, 20% antioxidant flame retardant, 2% polyethylene wax, and 1% calcium stearate. After stirring and dispersing evenly, melt blend at 280℃, extrude and granulate to obtain the finished product.

[0021] Example 2: Step S1: γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water were mixed and stirred at 62°C for 3 hours to obtain a hydrolysate; titanium dioxide, anhydrous ethanol, and deionized water were mixed and stirred for 25 minutes to obtain a dispersion; the hydrolysate and dispersion were mixed and stirred at 27°C for 3 hours. After the reaction, the mixture was distilled under reduced pressure, washed, and dried to obtain modified titanium dioxide; when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water was 0.9:4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water was 0.25:8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide was 1.15:1. Step S2: Mix curcumin and ethanol aqueous solution, stir and dissolve at 27℃, then add modified titanium dioxide, continue stirring and react for 35 min. After stirring, centrifuge, wash and freeze dry to obtain antioxidant modified titanium dioxide; the mass ratio of curcumin to modified titanium dioxide is 1.4:2. Step S3: Under nitrogen atmosphere, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene were mixed and reacted at 67℃ for 2.5 h, then the temperature was raised to 97℃ and reacted for 8.5 h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain a bispirocyclic product. Under nitrogen atmosphere, the bispirocyclic product, modified titanium dioxide, and acetonitrile were mixed, and triethylamine was added dropwise. After the addition was completed, the temperature was raised to 82℃ and reacted for 22 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain flame-retardant modified titanium dioxide. When preparing the bispirocyclic product, the mass ratio of pentaerythritol, phosphorus oxychloride, and 4-dimethylaminopyridine was 27:82:0.1. When preparing the flame-retardant modified titanium dioxide, the mass ratio of the bispirocyclic product, modified titanium dioxide, and triethylamine was 3:11:2. Step S4: Add sodium lignosulfonate to sodium hydroxide solution, stir to dissolve, then add epoxide bromide, stir evenly, and heat to 57℃ for 27 hours. After the reaction is complete, precipitate, filter, and dry to obtain epoxide lignin; the mass ratio of sodium lignosulfonate to epoxide bromide is 1:2.3; the concentration of sodium hydroxide solution is 8 wt%. Step S5: Epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to N,N-dimethylformamide, stirred evenly, and then heated to 125℃ for 5.5 h. After the reaction was completed, the mixture was rotary evaporated, washed, and dried to obtain an antioxidant flame retardant. The mass ratio of epoxidized lignin to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was 1:0.8. Step S6: By mass fraction, mix 62% PET, 10% antioxidant modified titanium dioxide, 5% flame retardant modified titanium dioxide, 20% antioxidant flame retardant, 2% polyethylene wax, and 1% calcium stearate. After stirring and dispersing evenly, melt blend at 260℃, extrude and granulate to obtain the finished product.

[0022] Example 3: Step S1: γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water were mixed and stirred at 60°C for 2.5 h to obtain a hydrolysate; titanium dioxide, anhydrous ethanol, and deionized water were mixed and stirred for 20 min to obtain a dispersion; the hydrolysate and dispersion were mixed and stirred at 25°C for 2.5 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed, and dried to obtain modified titanium dioxide; when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water was 0.9:4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water was 0.25:8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide was 1.15:1. Step S2: Mix curcumin and ethanol aqueous solution, stir and dissolve at 25℃, then add modified titanium dioxide, continue stirring and react for 30 min. After stirring, centrifuge, wash and freeze dry to obtain antioxidant modified titanium dioxide; the mass ratio of curcumin to modified titanium dioxide is 1.4:2. Step S3: Under nitrogen atmosphere, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene were mixed and reacted at 65℃ for 2.0 h, then the temperature was raised to 95℃ and reacted for 8 h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain a bispirocyclic product. Under nitrogen atmosphere, the bispirocyclic product, modified titanium dioxide, and acetonitrile were mixed, and triethylamine was added dropwise. After the addition was completed, the temperature was raised to 80℃ and reacted for 20 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain flame-retardant modified titanium dioxide. When preparing the bispirocyclic product, the mass ratio of pentaerythritol, phosphorus oxychloride, and 4-dimethylaminopyridine was 27:82:0.1. When preparing the flame-retardant modified titanium dioxide, the mass ratio of the bispirocyclic product, modified titanium dioxide, and triethylamine was 3:11:2. Step S4: Add sodium lignosulfonate to sodium hydroxide solution, stir to dissolve, then add epoxide bromide, stir evenly, and heat to 55℃ for 25 hours. After the reaction is complete, precipitate, filter, and dry to obtain epoxide lignin; the mass ratio of sodium lignosulfonate to epoxide bromide is 1:2.3; the concentration of sodium hydroxide solution is 8 wt%. Step S5: Epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to N,N-dimethylformamide, stirred evenly, and heated to 120℃ for 5 hours. After the reaction was completed, the mixture was rotary evaporated, washed, and dried to obtain an antioxidant flame retardant. The mass ratio of epoxidized lignin to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was 1:0.8. Step S6: By mass fraction, mix 62% PET, 10% antioxidant modified titanium dioxide, 5% flame retardant modified titanium dioxide, 20% antioxidant flame retardant, 2% polyethylene wax, and 1% calcium stearate. After stirring and dispersing evenly, melt blend at 250℃, extrude and granulate to obtain the finished product.

[0023] Comparative Example 1: The antioxidant modified titanium dioxide and flame retardant modified titanium dioxide were replaced with titanium dioxide, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Sodium lignosulfonate was added to sodium hydroxide solution, stirred and dissolved, and then epichlorohydrin was added. After stirring evenly, the temperature was raised to 60°C and reacted for 30 hours. After the reaction was completed, precipitate, filter, and dry to obtain epoxidized lignin; the mass ratio of sodium lignosulfonate to epichlorohydrin was 1:2.3; the concentration of sodium hydroxide solution was 8 wt%. Step S2: Epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to N,N-dimethylformamide, stirred evenly, and then heated to 130℃ for 6 hours. After the reaction was completed, the mixture was rotary evaporated, washed, and dried to obtain an antioxidant flame retardant. The mass ratio of epoxidized lignin to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was 1:0.8. Step S3: By mass fraction, mix 62% PET, 15% titanium dioxide, 20% antioxidant flame retardant, 2% polyethylene wax and 1% calcium stearate, stir and disperse evenly, then melt blend at 280℃ and extrude granulate to obtain the finished product.

[0024] Comparative Example 2: The antioxidant flame retardant was replaced with PET, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water were mixed and stirred at 65°C for 3.5 h to obtain a hydrolysate; titanium dioxide, anhydrous ethanol, and deionized water were mixed and stirred and dispersed for 30 min to obtain a dispersion; the hydrolysate and dispersion were mixed and stirred at 30°C for 3.5 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed, and dried to obtain modified titanium dioxide; when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water was 0.9:4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water was 0.25:8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide was 1.15:1. Step S2: Mix curcumin and ethanol aqueous solution, stir and dissolve at 30℃, then add modified titanium dioxide, continue stirring and react for 40 min. After stirring, centrifuge, wash and freeze dry to obtain antioxidant modified titanium dioxide; the mass ratio of curcumin to modified titanium dioxide is 1.4:2. Step S3: Under nitrogen atmosphere, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene were mixed and reacted at 70℃ for 3.0 h, then the temperature was raised to 100℃ and reacted for 9 h. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain a bispirocyclic product. Under nitrogen atmosphere, the bispirocyclic product, modified titanium dioxide, and acetonitrile were mixed, and triethylamine was added dropwise. After the addition was completed, the temperature was raised to 85℃ and reacted for 25 h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain flame-retardant modified titanium dioxide. When preparing the bispirocyclic product, the mass ratio of pentaerythritol, phosphorus oxychloride, and 4-dimethylaminopyridine was 27:82:0.1. When preparing the flame-retardant modified titanium dioxide, the mass ratio of the bispirocyclic product, modified titanium dioxide, and triethylamine was 3:11:2. Step S4: By mass fraction, mix 82% PET, 10% antioxidant modified titanium dioxide, 5% flame retardant modified titanium dioxide, 2% polyethylene wax and 1% calcium stearate, stir and disperse evenly, then melt blend at 280℃ and extrude granulate to obtain the finished product.

[0025] Flame retardant performance test: Referring to GB / T 2406.2-2009 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test", the finished PET masterbatch prepared by this invention was injection molded to obtain type I sample; the oxygen index value of the sample was recorded.

[0026] Antioxidant performance test: The finished PET masterbatch prepared in this invention was melt-extruded and cast (160-180℃) to obtain PET film. The PET film was cut into 2×2cm samples, and the samples were added to DPPH solution (0.2mmol / L). After stirring in the dark for 24h, the sample solution was obtained. The absorbance (A1) of the sample solution at a wavelength of 517nm was measured by spectrophotometry. Then, the absorbance (A0) of the DPPH solution without the sample added, after stirring under the same conditions, was measured by spectrophotometry. The free radical scavenging rate (%) was calculated by substituting the data into the formula: (A0-A1)100% / A0. The results are shown in the table below:

[0027] Conclusion: In Examples 1-3, the dosage remained unchanged, with only some reaction parameters modified. Experimental data showed no significant fluctuations in the performance of the samples.

[0028] Comparative Example 1: The antioxidant modified titanium dioxide and flame-retardant modified titanium dioxide were replaced with ordinary titanium dioxide, while the rest remained the same as in Example 1. The experimental data showed that, compared with Example 1, the oxygen index decreased to 30.5% and the free radical scavenging rate decreased to 85.1%. The reason for this is that the antioxidant modified titanium dioxide and flame-retardant modified titanium dioxide contain functional antioxidant materials and functional flame-retardant materials. Therefore, after replacing them with ordinary titanium dioxide, the antioxidant performance and flame-retardant performance decreased, resulting in a decrease in the oxygen index and free radical scavenging rate.

[0029] Comparative Example 2: The antioxidant flame retardant was replaced with PET, and the rest was the same as in Example 1. The experimental data showed that, compared with Example 1, the oxygen index decreased to 24.2% and the free radical scavenging rate decreased to 62.3%. The reason for this is that the antioxidant flame retardant contains synergistic flame retardant groups and sodium lignosulfonate with good antioxidant properties. Therefore, after replacing it with PET, the antioxidant performance and flame retardant performance decreased, which in turn led to a decrease in the oxygen index and free radical scavenging rate.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.

[0031] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing antioxidant and flame-retardant PET masterbatch, characterized in that: The process includes the following steps: mixing PET, modified pigments, antioxidants, flame retardants, dispersants, and lubricants, stirring and dispersing them evenly, followed by melt blending, extrusion granulation, and finally obtaining the finished product; The modified pigments include antioxidant modified titanium dioxide and flame-retardant modified titanium dioxide. The antioxidant modified titanium dioxide is obtained by loading the biomass antioxidant curcumin onto the surface of titanium dioxide pigment. The flame-retardant modified titanium dioxide is obtained by grafting flame-retardant bicyclic products onto the surface of titanium dioxide pigment. The antioxidant flame retardant is obtained by grafting phosphorus heterocyclic flame retardant materials onto the surface of lignin, an antioxidant material.

2. The method for preparing antioxidant flame-retardant PET color master batch according to claim 1, characterized in that: The content of each component in the finished product is as follows (by mass fraction): 55-65% PET, 10-15% antioxidant modified titanium dioxide, 5-10% flame retardant modified titanium dioxide, 20-25% antioxidant flame retardant, 2-3% dispersant, and the balance is lubricant.

3. The method for preparing antioxidant flame-retardant PET color master batch according to claim 2, characterized in that: The dispersant is polyethylene wax; the lubricant is calcium stearate; and the melt blending temperature is 250-280℃.

4. The method for preparing an antioxidant and flame-retardant PET masterbatch according to claim 2, characterized in that: The preparation process of antioxidant modified titanium dioxide is as follows: Step S1: Mix γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water, and stir at 60-65℃ for 2.5-3.5 h to obtain a hydrolysate; mix titanium dioxide, anhydrous ethanol, and deionized water, and stir and disperse for 20-30 min to obtain a dispersion; mix the hydrolysate and the dispersion, and stir and react at 25-30℃ for 2.5-3.5 h. After the reaction is completed, distill under reduced pressure, wash, and dry to obtain modified titanium dioxide. Step S2: Mix curcumin and ethanol aqueous solution, stir and dissolve at 25-30℃, then add modified titanium dioxide, continue stirring and reacting for 30-40 minutes. After stirring, centrifuge, wash and freeze dry to obtain antioxidant modified titanium dioxide.

5. The method for preparing an antioxidant and flame-retardant PET masterbatch according to claim 4, characterized in that: In step S1, when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water is (0.8-1.0):4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water is (0.2-0.3):8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide is (1.1-1.2):1; in step S2, the mass ratio of curcumin to modified titanium dioxide is (1.3-1.5):

2.

6. The method for preparing an antioxidant and flame-retardant PET masterbatch according to claim 2, characterized in that: The preparation process of flame-retardant modified titanium dioxide is as follows: Step 1: Mix γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water, and stir at 60-65℃ for 2.5-3.5 h to obtain a hydrolysate; mix titanium dioxide, anhydrous ethanol, and deionized water, and stir and disperse for 20-30 min to obtain a dispersion; mix the hydrolysate and the dispersion, and stir and react at 25-30℃ for 2.5-3.5 h. After the reaction is completed, distill under reduced pressure, wash, and dry to obtain modified titanium dioxide. Step 2: Under nitrogen atmosphere, pentaerythritol, phosphorus oxychloride, 4-dimethylaminopyridine, and chlorobenzene are mixed and reacted at 65-70℃ for 2.0-3.0h, then the temperature is raised to 95-100℃ for 8-9h. After the reaction is completed, the mixture is cooled, filtered, washed, and dried to obtain the bispirocyclic product. Under nitrogen atmosphere, the bispirocyclic product, modified titanium dioxide, and acetonitrile are mixed, and then triethylamine is added dropwise. After the addition is completed, the temperature is raised to 80-85℃ for 20-25h. After the reaction is completed, the mixture is rotary evaporated and dried to obtain the flame-retardant modified titanium dioxide.

7. The method for preparing an antioxidant and flame-retardant PET masterbatch according to claim 6, characterized in that: In step 1, when preparing the hydrolysate, the mass ratio of γ-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water is (0.8-1.0):4:1; when preparing the dispersion, the mass ratio of titanium dioxide, anhydrous ethanol, and deionized water is (0.2-0.3):8:1; when preparing the modified titanium dioxide, the mass ratio of γ-aminopropyltriethoxysilane and titanium dioxide is (1.1-1.2):1; in step 2, when preparing the bispirocyclic product, the mass ratio of pentaerythritol, phosphorus oxychloride, and 4-dimethylaminopyridine is 27:(80-85). 0.1; When preparing flame-retardant modified titanium dioxide, the mass ratio of bispirocyclic product, modified titanium dioxide, and triethylamine is 3:(10-12):

2.

8. The method for preparing an antioxidant and flame-retardant PET masterbatch according to claim 2, characterized in that: The preparation process of antioxidant flame retardants is as follows: Step (1): Add sodium lignosulfonate to sodium hydroxide solution, stir to dissolve, then add epoxybromopropane, stir evenly, and heat to 55-60℃ for 25-30h. After the reaction is completed, precipitate, filter and dry to obtain epoxidized lignin. Step (2): Add epoxidized lignin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to N,N-dimethylformamide, stir evenly, and then heat to 120-130℃ for 5-6 hours. After the reaction is completed, the antioxidant flame retardant is obtained by rotary evaporation, washing and drying.

9. The method for preparing an antioxidant and flame-retardant PET masterbatch according to claim 8, characterized in that: In step (1), the mass ratio of sodium lignosulfonate to epoxypropane is 1:(2.0-2.5); the concentration of sodium hydroxide solution is 7-10wt%; in step (2), the mass ratio of epoxidized lignin to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(0.7-0.9).

10. An antioxidant and flame-retardant PET masterbatch, characterized in that, Prepared by the preparation method according to any one of claims 1-9.

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